Transient Cerebral Ischemia in Mice

Focal brain ischemia was induced by transient intraluminal MCAO using a monofilament. Animals were first anesthetized with 2.5% avertin (20 µl/g, i.p.). A midline ventral neck skin incision was made, the temporal muscle was retracted, and the left carotid artery was exposed and isolated. After the common carotid artery and the external carotid artery were ligated, a silicone-coated monofilament (Doccol, Sharon, MA, USA) was inserted into the left internal carotid artery through an incision in the common carotid artery until it reached the origin of the left MCA where mild resistance was encountered (9–10 mm). One hour after blocking the MCA, the monofilament was withdrawn to restore the blood flow, and the skin was sutured. Transcranial laser-Doppler flowmetry (PeriMed) was utilized to monitor the regional cerebral blood flow (CBF) and ensure successful ischemia and reperfusion. MCA occlusion was determined by a reduction of more than 70% in CBF compared to that at baseline. The body temperature of each mouse was maintained at 37 °C ± 0.5 °C with an electric blanket pad throughout the procedure. No significant differences were noted between Vdr-cKO and control mice in regional CBF at baseline, during ischemia and reperfusion (Additional file 1: Fig. S2G, H), as well as in body temperature and blood pressure during MCAO or sham procedure. Mice were returned to the cages after regaining consciousness.